Technical Field
Embodiments described herein are related to power management in integrated circuits.
Description of the Related Art
Integrated circuits are a key component of most mobile devices, such as smart phones, personal digital assistants, tablet computers, laptop computers, etc. Mobile devices are often operated from a limited energy source such as a battery. Accordingly, energy efficiency (e.g. efficient power consumption) is an important metric of integrated circuits.
Power consumption includes both dynamic power consumption and leakage power consumption. Dynamic power is consumed in the operation of the circuitry in the integrated circuit to perform the functions for which the integrated circuit is designed. For example, digital logic circuitry switching from binary zero to binary one, and vice versa, consumes power. Leakage power is consumed due to physical device effects, in which a certain amount of current is “leaking” through the physical structure of transistors when the transistors are “off” (not actively conducting current in response to the control terminals of the transistors). Leakage current occurs whenever the circuitry is powered on and is proportional to the power supply voltage provided to the integrated circuit as well as other factors such as temperature. As semiconductor fabrication technology has continued to shrink the feature sizes of transistors, leakage power consumption has increased as a percentage of total power consumption.